Choosing a Mini-Split Comes Down to Room-by-Room Sizing, Head Placement and Replace or Supplement

Choose a mini-split by where ductwork is hard to run, by room-by-room sizing and by where each head and the outdoor unit will go, and ask each installer for the calculations and the maintenance plan in writing. This is general information and not engineering advice, and Good Haus is a free matching service and not a contractor.

Where does a mini-split fit?

ENERGY STAR says mini split heat pumps, also called ductless heat pumps, do not need ductwork in order to be installed. It says that if you are planning an addition or renovation where running ductwork will be difficult, you can still install a heat pump to heat and cool a portion of your house. New York State’s MyEnergy portal calls it typically the simplest, least expensive heat pump system. Ask the installer why a mini-split suits each room you want it in, and ask what the alternative would involve.

How should the system be sized?

ENERGY STAR says installing properly sized HVAC equipment for your home is essential to getting the best performance and comfort, and that a system that is either too large or too small for its intended space will struggle to meet your home comfort needs. It says your contractor should verify the proper size system for your home using a tool called “Manual J”. MyEnergy says to ask for room-by-room heating and cooling calculations. Ask each installer to show the calculation for each room and the size of each head, not only a total.

Where do the heads and the outdoor unit go?

MyEnergy suggests asking how many ductless heads you will need and what is the best location for each one, and whether you can avoid heads directly above where people eat or sleep. Picture a bedroom where the bed sits under the only wall that fits the head: ask the installer for a layout drawing of the heads and the outdoor unit before you accept a bid.

Will it handle winter?

ENERGY STAR says that if you live in a climate where winter temperatures regularly dip below freezing, you should talk to your contractor to choose an ENERGY STAR unit suited to your particular home. Ask the installer which model is rated for your coldest weeks and whether you will keep a back-up heat source.

Does it replace your heating or supplement it?

MyEnergy says you can install multiple mini-splits to handle all of the heating and cooling in your home and replace your existing systems. Ask the installer whether the quote replaces your current system or supplements it, because the number of heads and the budget change with that choice.

What does upkeep involve?

MyEnergy suggests asking how often you should clean or change air filters, whether annual service is needed and what the expected lifespan and warranty are. Ask for the maintenance steps and the warranty terms in writing before you sign.

What should you ask before you request quotes?

1. Ask why a mini-split suits each room.
2. Ask for room-by-room calculations.
3. Ask for a layout of the heads and the outdoor unit.
4. Ask which model is rated for your winters.
5. Ask for the maintenance steps and warranty in writing.

Put the Room Calculations in Every Mini-Split Quote Request

Give every installer the same room list and ask for the same calculations when you request room addition quotes, so each bid sizes and places the same mini-split system.